Not everybody has a janitor on a nightly basis. Many clean on a weekly basis.
On most urinals the wash down is not all that great any way, it doesn’t cover much area so there is much surface left, plus many guys don’t bother to flush a urinal, which means your nose is directly above a urine filled p trap and often the water to the urinal isn’t on anyway so again, no benefits.
If you don’t clean the bathrooms anyway, then the tiny additional unwashed surface of a waterless urinal with a barrier blocking the p trap is about the same or even better than a typical urinal.
My experience is that the waterless urinals are in bathrooms that do receive janitor service though, I have yet to see one in a dump.